Air-brake appliance.



W. A. SKINNBR & T. F. GAIN.

AIR BRAKE APPLIANCE. APIfLIGATION FILED 0012s, 1902.

Patented Nov. 26, 1912.

7 SHEETS-SHBET1.

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W. A. SKINNERK: T. P. CAIN.

AIR BRAKE APPLIANCE. 'APPLIOATION FILED OCT. 23, 190$.

Patnted Nov. 26, 1912.

' '7 SHEBTSSHEET 2.

W. A. SKINNER'GI: T. F. CAIN. AIR BRAKE- APPLIANCE. IAPPLIGATYION TILED OCT. 23, 190-8.

Patented NOV. 26,1912.

7 SHE-ETfirSHEET 3.

W. ASKINNER & T. F. G I

AIR BRAKE APPLIANCE. 7 APPLICATION FILED OUT. 23, 1908.

Patented Nov. 26, 1912.

v SHEETSSHEEIT, 4.

W. A. SKINNER & T. F. GAIN.

AIR BRAKE APPLIANCE.

AFPLIGATION FILED 00323, 1908.

Patented Nov. 26, 1912.

7 SHEETS SHEET 5.

31411011 EorA W J S/azL/ww/v Ji 1' 6 ou /'10 g u 00 m 1 o W a W. A. SKINNBR & T. F. GAIN.

AIR BRAKE APPLIANCE.

' I APPLICATION FILED OCT. 23, 1903.

1,045,448, Patented Nov. 26, 1912.-

7 SHEETSSHEET 6.

Aux. Resp/41 E Q I 40 4 2- 52 3\ 4 mm rirc zw.

W. A. SKINNER & T. P. CAIN.

AIR BRAKE APPLIANCE.

APPLICATION FILED OUT. 23, 1908.

I 1,045,448. Pagented Nbv.26,1912

7 SHEETS-SHEET 7.

I @wvemicw toms, and relat of the parts t W'llLTEE A. SKICJNIEJR, "If/l? MOBERLY, AND THOMAS E. GAIN,

or lv'ioivrooicnnv CITY,

MISSOURI.

AER-BRAKE APPLIANGE. I

Application filed October 23 ToaZZ whom it may concern:

, Be it hnovv'n that We, WALTER A. SKIN- Nicn and THDMAS F. CAIN, citizens of the United States, residing at Moberly, Randolph county, and Montgomery City, Montgomery county, respectively, Stote of Missouri, i eve invented certain'new, and useful Improvements in iiinljrake Appliances, of which the following is o specification. s

This invention eoniprehends certain new and useful improvements in air brake syses particularly to an iinproved safety appliance in the form of an air valve attachment which may he usedv either as o separate adjunct or cast integral With either the ordinary or quick-action triple valve.

()ne of the objects oi the invention is an air brake appliance of this cham'cter, so constructed and arranged that there may be automatic and straight air on all the cars of the train, with loot one train line. The invention also has for its object 2i device of this character, by the use of which the snzziliery reservoirs on. cars can he re charged after a brake application, Without releasing the hralres, Wlierehy, the instantthe brakes are released, the auxiliary reeervoii' has standard press-ore for full service or emergency application, and whereby the brake cylinders can be kept charged to a standard pressure oi 50 lbs. with a train stsnd on a down grade, and the auxiliary "*b reservoirs charged to a, standard pressure of say '70 lbs. or any train line pressure carried, so long as the air is pumped from the engine. "And a further object oi the invention is a safety appliance in an air brake system, so constructed and arranged that, if a train equipped with the invention Were to get away on a heavy grade before the euxiliary reservoirs were charged, all brake cylinders of the cars could be charged with straight air, thereby charging the auxiliary reservoirs and the brake cylinders at the same time.

With this and other objects in vietv as Will more fully appear as the description proceeds, the invent-ion consists in certain constructions, arrangements and combinations at We shell hereinafter fully describe and claim.

For a full understanding of the: invention and the merits thereof, and to acquire a knowledge of the details of construction.

Specification of Letters Patent.

- anism inverted to show the relat-i ton ondpiston rod:

Patented Nov. 28, 1912.: 1908. Serial No. 459,229.

reference is to be had tov the following description and accompanying drawings, in which:

Figure l is a, plan View of the brake mechanism of a car equipped with the improvements of our invention, parts being shown in section and other ports broken away; Fig. 2 is it horizontal sectional view of our improved air brake appliance, on an enlarged scale taken on an ir egular line extending through the brake clinder connection and dipping to show the main pie ton valve; Fig. 8 is a transverse sectional view thereof, the section being taken on a plane Where the connections of the appliance .With the brake cylinder and train pipe-are shown; Fig. 4 1s a vertical longitudinal sec tional View through the governor mechanism of the appliance; Fig. 5 is a. detail plan view of the seat for the slide valve of the governor mechanism; Figs. 6 and 7 are, respectively, a to plan and longitudinal section of said slide valve, its piston and piston rod being shown in side elevation; Figs. 8. 9, and ii are detail sectional views illustrating the correlated positions of the slide valve and its seat for different operations of the appliance, Figs. 8 and 9 being sections taken. substantially on the line B of Fig. 5, as regards the valve seat, and Figs. 10 and 11 being sections token substantially on the line A-A of Fig. 5; Fig. 12 is a face view of the governor mechve arrange ment of grooves and ports that correspond with similar grooves and ports in the adjoining face of the main casing of the appliance; Fig. 13 is a view of such face, it being understood that Figs. 12 and 13 would match if one were to be placed upon the other with Fig. 12 turned down upon Fig. 13; Fig. let is adetoil perspective view of the seat for the slide valve of the governor mechanism: Fig. 15 is a detail perspective view of said slide valve on its seat, together with its pis- 16 and 17 are diagrammatic sectional views showing the operation of the governor slide valve: Fig.

'18 1s a section taken transversely of Fig. 2

and centrally through the valve.

Corresponding and like parts are referred to in the following description and indicated in all the views of the loo-Wings by the so me reference characters.

governor slide T he said Referring to-the drawings wherein the invention is illustrated as separate from'the triple valve, A designates a triple valve, B a brake cylinder, 1) a train pipe line and E our improved safety appliance. This latter is connected 'to the exhaust. port of the-triple valve A by are also arranged in Fig. 2, it will be assumed that a service application has been made and the engineers brake valve is on the lap position, that it is desired to recharge the auxiliary reservoirs of the diiferent cars of the train without releasing the brakes, and that it is then desired to release the brakes. Referring now more particularly to Fig. 2, the brake cylinder air enters the casing E through the port 1 and thence passes through the passage 2 into a hollow cap-nut 3, where the air acts upon a winged valve 4 to force it off its seat on said nut, the said valve being secured on the same rod as a piston 5 working in abushing, as shown. air from the brake cylinder, passes the valve-4, flows through the passage 6, around the piston 5 and its bushing, and into the valve chamber 7 where it acts upon a piston 8 which is at this time in the position illustrated in dotted lines in said Fig. 2, and in full. lines in Fig. 16 thereby forcing said piston to the left. The piston 8-is secured to a piston rod or valve stem 9 to which the piston valve 10 is rigidly connected, so that as the brake cylinder air moves the piston 8 to the left, the said piston carries the valve 10 with it, and the packing rings 11 and 12 of said valve overlap the port 13 which leads from the triple exhaust port and pipe (i. thereby preventing the air from flowing through the exhaust port of the triple valve to the atmosphere, even with the triple valve in the release position as illustrated in Fig. 1.

I noted, as best seen inFigs. 2 and 3, that these packing rings 11 and 12, when they overlap the port 13. separate said port from the passage 14 which is the final exhaust and which leads to the atmosphere through the side of the-casing E, as indicated in dotted lines in Fig. 3. Thus it will be seen that the auxiliary reservoi C can be charged through the ordinary feels-groove in the slide valve piston of the triple valvewhile the engineers brake valve is in the running position, without releasing the brakes, the exhaust air from the triple being prevented from reaching the atmosphere by being stopped at the port 13, and prevented from flowing out through the port and passage 14:. The main valve of .the safety appliance (designated 10) is now in working position,

C an auxiliary reservoir,

It isto be as illustrated in full lines in Fig. 2 15 designates a check valve which is in the passage leading from the triple valve exhaust port to the port 13, as indicated in dotted lines inFigs. 2 and 3, and which permits the air to pass said valve in a direction from the triple exhaust, but which prevents the train pipe alr from flowing into the brake cylin'der through the exhaust cavity in the triple slide valve when the engineers brake :valve is put in running position and the triple forced to the release position;

It will be observed, by particular reference to Fig. 2, that when the main valve 10 of our appliance has moved to the working position illustrated in full lines, in suchview, the valvelO will overlap the passage 6, thereby shutting off communication-between such passage and the chamber to the right of the piston 8. As the train pipe air is fed into the auxiliary reservoir C through the feed groove in the triple valve piston,

it is also flowing through the pipe cl past a valve 16 (Fig.3) which is held ofiits 1 seat by a piston 50 lbs. tension the rod 17 and bearing upon the piston 18 mounted in one of the cavities or bushings of the governor casing 20. The train pipe air thus flows past the valve 16, through apassage 21, into the valve chamber' 7, back of the main piston valve 10 of our 9. pliance, and also flows from said cham er and through a cross passage 22-into the chamber .23 in which the piston 5 works, thereby immediately forcing the piston 5 back and seating the valve 4; so as to effectually cut 05 or prevent any more air from flowing from the brake cylinder. The train pipe air also flows through a passage 24-. underneath a check valve 25, is stopped by a valve '27 secured to a piston 28 and encircled by a spring 29 having a tendency to force the valve oti its seat. This valve is, however, held on its seat by the train line air passing through the passage 30 to the side of the piston remote from rod 17 and held under sayby a spring 19 encircling' to a valve seat 26, where it the spring, as shown in Fig. 2, until the air pressure on opposite sides of the piston 28 balances, whereupon the spring 29 will act to open the valve 27 and permit straight air to be fed into the brake cylinder. it will thus be seen that by our invention there can be autiajnatic and straight air on all of the cars witiifbut a single train line, and that if, for example, a train was to get away on a heavy grade before the auxiliaries had been charged to standard pressure, all of the brake cylinders of, the cars eould be fed with straight air, ervoirs and the brake cylinders at the same time.

thereby charging the res- As will be best seen in Fig. 2, the short valve overlaps the exhaust port of the cylinder and the exhaust port leads in between said packing rings so that air can flow from the triple valve exhaust only when the main valve 10 is in the release position. Train pipe air is cut off and can not get into the ports 22 and 22 when the main valve 10 is in the release position indicated by dotted lines in Fig. 2. In further explanation of the port 22, it may be stated that in the release position of the main piston valve'lO, shown in dotted lines in Fig. 2, the exhaust cavity in the valve 10 will overlap the port 22 28 well as the ports 13 and 14 leading from. the brake cylinder to the atn'ospherc. This is to prevent the exhaust of the brake cylinderpressure from below the piston 5,

so that said piston will hold the valve 4 on its seat in order that the brake cylinder air may not raise the valve 4 from its-seat and move the main valve 8 and piston valve 10 to the left, that is, to the working position. If there were no pressure below the piston 5, the brake cylinder airabove the valve 4 would flow out and thereby place the main valve 10 again in working position.

32 designates a passage around the piston 8, said passage connectingthrough the port 53 with the passage 33 leading tothe atmosphere at one end of the casing 1*), this passage being formed by two grooves formed in the opposing faces of the main easing of the appliance andthe casing 20 of the governor mechanism, as best seen in Figs. 12 and 13. In the position of the parts when the triple exhaust is cut off and the brake cylinder fed \vithst-raight air, it will be noted that the cavity in the main piston valve 10 overlaps the passage (3 leading into the valve chamber 7, and if train pipe air should be drawn oilf to such a low pressure that the brake'cylinder air would force the valve 4 from its seat, it is obvious that the brake cylinder air could not escape to the atmosphere through the port and passages 32, 53 and 33 around the piston 3. lVhen the main valve 10 is moved to the release position shown in'dotted lines in Fig. 2,-as hereinafter more fully described, it is clear that the packing ring 12 will uncover the port 14 and letwhatair pressure might have been over the piston 5 out to the atn'iosnhere-through the passage-6 and passage 14before it uncovers the port 13 to connect the triple valve exhaust port to the atmosphere. Furthermore, when this main valve 10 is in the release position, the air passes from the valve side of the piston 5, through the passage 6, and around the piston 8 by way of the by-pass groove 34 overlapping the packing ring of the piston 8, and to the atmosphere through the ports 53 and We have thus far described how, after a service application of the brakes has been made and it is desired to recharge the auxiliaryreservoir, the piston 10 is moved to working position from the release position which'takes place at the time of the brake application, the recharging of the auxiliary reservoir being accomplished by moving the engineers brake valve to the running position, there being no change in the position of the parts of our appliance during this recharging operation, it being of course understood that the placing of the engineers brake valve in running position forces the triple valve to the release position, which is the position for recharging the auxiliary reservoir. There is, then, no change in the position of the parts of our apparatus during this recharging operation, but when the engineers brake valve is placed in full release position, our appliance also moves to full release position. I

We shall now describe how the main valve 10 of our appliance is moved to a position to release the brakes; that is to say, to a position where the cavity in the piston valve 10' overlaps the ports 13 and 14'so as to allow the brake cylinder air from the triple valve exhaust port to escape tothe atmos' phere through the said ports L-l'and 14. Auxiliary reservoir pressure connects with the passage 34 extending entirely through the valve casing E, as-i'mlicated in dotted lines in Figs. land 2 and shown most clearly in Fig. 18, and connects with a port 35 leading by a diagonal passage, as indicated in Figs. 12 and 13, to a port 36 in the governor casing 20. The port 35 also "opens into the governor casing above the piston 36, StIHl' iston bein connected to a rod 37 v a h encircled by a spring 36 which has say about lbs. tension. The port 36 is connected to a port 39 in avalve seat 40, and 41 designates the governor slide valve which is rigidly connected to the piston rod 37 by collars or the like as shown. The slide valve 41 is formed with a cavity 42 which, in the working of the piston valve 10, overlaps the port 39 and a port 43, as best seenjn Figs. 8

10 and 17, the port 43 being connected by a passage 44 back of the valve seat with a port 45. This port 45 is designed to regis-' ter with another cavity 46 formed inthe valve 41, and is connectedby means of a passage 47 with a piston chamber 48 at a point below the piston 49 therein. This piston 49 is connected to a piston rod 50 to which a valve 51 is also connected, said valve 51 normally closing a passage 52 which leads from the train line passage 24 at the juncture of the same with the cross passage 22 (see Fig. 2). 54 designates a port in the valve seat 40 leading to a passage 55, the latter in turn leading to the left side of a piston 8. connected to the piston rod 9 in and communicates with the passage leading from the port 13 so as to allow any train pipe air that might leak past the piston valve 10 (packing ring 11) to escape to the atmosphere through the passage 14 and not force the-piston valve 10 to the working position by actingupon the rear face of said piston valve in the chamber 7. It is to be understood that the port 31 serves no purpose except when the main valve piston 10 is in the release position.

When it is desired to place the valve 10 in the release position, the engineers brake valve is placed in full release position which causes the pressure. .to rise 20 or 30 lbs. (depending up'on whatever main reservoir pressure is carried). This pressure is then on top of the valve 41 and under the piston 36 (Fig.4) and causes the piston 36 to move away from the greater pressure under it, carrying-the slide valve 41 with it, which allows train line air to passthrough the port 54 (see Figs. 2, 9,'11'and 16) in'the slide valve seat, the air passing to' the front of the piston 8 by means of the passage 55, and also exhausting the auxiliary reservoir pressure from under the piston 49 and at the same time porting train line air on top of piston '49 which causes said piston to move down, carrying with it the valve 51. There is, then, a direct communication from the passage 22 through the; passage '52 and through the port 56 and passage to the front face of the iston 8, and the pressure onsuch piston will then force the valve 10 to the right or release position, the air which iglthen trapped at the right end of the valve 0 amber passing through the passages 22, 52, and 55 so that it will not act againstthe valve to prevent its movement. After the piston 36 has made one upward stroke as just described, it will return to the position shown in Fig. 4 as soon as the brake valve on theengine is placed in running'position,

. when the air pressure will charge slowly to '70 lbs. or to whatever normal pressure the brake valve is set to carry. Manifestly, the valve 41 is connected to the piston 36 and makes whatever movements the. piston makes. The train line air under the piston 36 will soon equalize with the auxiliary reservoir pressure on top of said piston and the piston wlll then move down 111 its cylinder as .there 1s an excess pressure exerted by the spring 38 on the top of said piston.

It is understood that the auxiliary reservoir pressure on topof the'piston 36 is ported from the auxiliary reservoir where it comes through the triple valve. The slide valve 41 will always be' returned to the position shown in Figs. '4, 17 and 18 as soon as the brake valve on the engine is return'edtofi running position and the auxiliary reservoir equalizesfwith the train pipe pressure. When the valve 10 thus moves totheright or release position, it shuts 01f the train lme air from the passage 52 and underneath; the disk valve 51, also shutting the train-line pressure off from the left hand face of the larger piston 8. When the slide valve 41 returns to the position just named, it ports auxiliary reservoir air under the piston 49 which will thereupon seat the valve 51. There is always auxiliary reservoir air under the piston 49 when the slide valve 41 is in'the position shown in Figs. 4, 17 and 18 and until the slide valve 41 .has made an upward movement, which will exhaust the auxiliary reservoir air from below the pistonv49. It is also understood that when the engineers brake valve is placed in full release position, the valve'1'6 is closed, whereby there will be more air pressure underneath the piston 36 than there is auxiliary air pressure above it. This sudden increase of air pressure under the piston 36' will cause it to rise so as to open the port 54, before the auxiliary reservoir air can balance on the top of the piston 36'.

Referring again to Fig. "2, air is removed from the left side of thepistonfi after it has forced the piston valve 10"to the release position, through the small groove around the piston 8 when it is in the release position, which connects with the port 53 leading to the passage 33 and to the atmos-' phere. When the piston valve 10 is in the release position,-it cuts off the train line air through the different ports and passages leading to the right of the piston 8. I

Having thus described the invention, what we claim is:

1. In an air brake system, the combination with an auxiliary reservoir, a brake cylinder, a train pipe, and a triple valve arranged to control the passage of air from the auxiliary reservoir to the brake cylinder and from the brakecylinder to the atmosphere and from the train pipe to the auxiliary reservoir, of means for automatically preventing the escape of the triple exhaust with the triple in release position and for simultaneously feeding straight air'from the train pipe into the brake cylinder.

2. The combination with an auxiliary reservoi'r, a brake cylinder and a triple valve arranged to control .the passage of air from the auxiliary reservoir to the brake cylinder and from the. brake cylinder to "the atmosphere, of a safety appliance embodying a casing having a port connection With the triple exhaust port and having another port leading to the atmosphere, a piston valve mounted in said casing and arranged in one position to separate said ports, whereby to prevent the escape of the exhaust from the triple valve, and means controlled by the air brake pressure for automatically moving said piston valve to such position with the triple valve slide valve in application position.

3. In an air brake system, the combina tion With a reservoir, a brake cylinder and a triple valve arranged to control the passage or" airfrom the reservoir to the brake cylinder and from the brake cylinder to the atmosphere, of a safety appliance embodying a casing having a port connecting with the triple valve exhaust port and a port leading to the atmosphere, a valve in said casing arranged in one position to separate said ports, whereby to prevent the escape of the triple valve exhaust, a piston connected to said valve and moving the same to such position, the said casing being provided with passages leading from the brake cylinder to a point back of said piston, a valve controlling said passages and arranged to he opened by the brake cylinder air and closed by the train line pressure.

4. In an air brake system, the cm'nhination with a. reservoir, a brake cylinder and a triple valve arranged to control the passage of air from the reservoir to the brake cylinder and from the brake cylinder to the atmosphere, of a safety appliance embodying a casing having a connection with the exhaust port of the triple valve and having another port leading to the atmosphere, a piston valve mounted in said casing and arranged iirone position to separate said ports, whereby to prevent the escape of the triple exhaust, a piston connected to said valve, the said casing being provided with passages leading to the back of the piston from the brake cylinder, a valve controlling said passages, a piston connected to said 'alve, and a train line having. connection with that side of said last named piston which would tend to close the last named valve, the said valve which is arranged to separate said ports before mentioned being provided with a cavity arranged to overlap one end or" the passage leading from the brake cylinder to the piston of said valve in the working position of the same.

5. In an air brake system, the comlanation with a reservoir, a brake cylinder and a triple valve arranged to control the passage of air from the reservoir to the brake cylinder and from the brake cylinder to the atmosphere, of a safety appliance embodying a casing having a'port connection with the exhaust port of the triple valve, and

another port leading the atmosph e a er piston valve arranged in one position to se arate said ports, whereby to prevent the escape of the triple exhaust, and a p'i'ton connected to, said valve, the said casing being provided with passages leading to the rear side of said piston from the brake cylin-i der, whereby brake cvlinder air may force the piston in a direction to carry the valve to Working position, the casing being also provided with a passage leading to the mosphere around said piston.

G. In an air brake system, the combination with a reservoir, a brake cylinder and a triple valve arranged to control the passage of air from the reservoir to the brake cylinder and from the brake cylinder to the atmosphere, of a safety appliance embody mg a casing having a port connection with the exhaust port in the triple valve and another port leading to the atmosphcremeans actuated by brake cylinder pressure for separating said ports in the release position of the triple valve slide valve for the PUFVJSQ specified, and a checl: valve in the leading from the triple valve exhaust port to the safety appliance, said check valve opening away from the triple valve exhaust port.

7. in an air brake system, the COH'lliinhtiOil with an auxiliary reservoir, a brake cylinder. a train pipe, and a triple valve arranged to control the passage of air from the auxiliary reservoir to the brake cylinder and from the brake cylinder to the atmos- 1 phere, and from the train pipe to the aunt iary reservoir, of means for automatically preventing the escape of the triple exhaust with the triple in release pos 2, and r feeding straight air from the train pipe into the brake cylinder.

8. In an air brake system, the combination with a reservoir, a brake cylinder, a triple valve arranged to control the passage of air from the reservoir to the brake cylinder and from the brake cylinder to the atmosphere,

and a train line arranged to "feed air lo the reservoir through the triple valve, in the release position of the latter, of means tor holding the exhaust from escapin from the j t, (11

brake cylinder through the triple valve, in the release position of'the latter, means For feedin strawht air to the bralre :1- diodes l with said holding means in the working position, a governor valve, and means :Lor movin said overnor valve into a )OSliilOIl m e, where tne tram hne'pressnre will move said holding means to the release position.

9. in an air brake system, the combination with a reservoir, a brake cylinder,

triple valve arranged to control the passage of air from the reservoir to the brake cylinder and from the brake cylinder to the atmosphere, and a train line arranged to feed air through the triple valve to the res ervoir, of a safety appliance embodying a casing having a port connection with the exhaust port of the triple valve and another port leading to the atmosphere, a piston valve arranged in working position to separate said ports, a piston secured to said valve, the casing being provided with pastion with a reservoir, a brake cylinder, a

sages leading from the brake cylinder to the piston, whereby the brake cylinder pressure may move the valve to working position, a governor valve, the casing being provided with passagesleading from the auxiliarv reservoir to the atmosphere and con trolled by said governor valve and also with passages leading from the train line to said valve, the valve being arranged in one position to admit train'line air to a piston of the first named valve, wherebyto move such valve to the release position, and means for automatically moving said governor valve to such position;

10. Inan air brake system, the combinatriple valve arranged to control the passage of air from the reservoir to the brake cylinder and from the brake cylinder to the atmosphere and a train line designed to feed air into the reservoir through the triple valve, of a safety appliance having a port connection with the exhaust port of the I triple and another port leading to the atmosphere, a main valve in said safety appliance arranged in working position to separate said ports for the purpose specified and arranged in the release position to connect said ports, means for automatically moving said valve to the working position, a piston 49in said safety appliance, the appliance being provided with an air' passage leading from, the train line to a point in front. of

"said valve, the'v'alve being provided with a piston designed to be actuated by train line pressure so as to move the said valve tothe release position, a valve controlling said passage and connected to said piston49, the appliance being also provided with passages leading from the reservoir below the piston as, a governor valve arranged to control the passage of reservoir air through the reservoir below said piston g9 and between'the piston 49 and main valve, and

inane re means for automatically .moving such governor valve to the position where it will exhaust the reservoir pressure to the atmosphere and admit train lineair to the front side of the piston which is connected to the first named valve.

11.1n an air brake system, the combination with a reservoir, a brake cylinder, a triple valve arranged to control the passage of air from the reservoir to the brake cylinder and from the brake cylinder to the atmosphere, and a train line adapted to feed air into the reservoir through the triple valve, means actuated by'the brake cylinder pressure for preventing the escape of the triple exhaust with the triple valve slide valve in the release position, means forcutting in straight air into the-brake cylinder with such holding means in the working position, and means for automatically cutting off such straight air when the brake cylinder pressure has reached a predetermined point.

12. In an air brake system, the combination with a reservoir, a brake cylinder, a triple valve arranged to control the passage of air from the reservoirto the brake cylinder and from the brake cylinder to the atmosphere, and a train line adapted to feed air into ,the reservoir through the triple valve, of a safety appliance embodying means actuated by brake cylinder pressure .for preventing the escape of the triple ex-.

haust with-:the triple valve slide valve in the release position, meansactuated by the train line pressure for automatically cutting oil the brake cylinder airfrom such first named means, means for preven'tin the feeding straight air into the brake cylinder, andmeans for feeding strai ht air into the brake cylinder automatica ly upon the equalization of brake cylinder and train 'line pressures.

In testimony whereof we aiiix our signatures in presence of two wltnesses.

WALTER A. SKINNER. [n 8.] THOMAS F. oanv. [n.s]

Witnesses:

JAs. L. Mo LINE, W. S. HIBBERT. 

